1. Field of the Invention
The present invention relates generally to devices, systems, and methods for the trenchless replacement of pipes, and particularly to such devices that are used to remove and replace water service pipes.
2. Description of the Prior Art
Water is typically supplied to buildings, whether commercial or residential, through water pipes that are buried in the ground. These water pipes are typically galvanized steel pipes, although copper, plastic and other pipe materials are sometimes utilized, and such water pipes typically have a diameter from approximately xc2xd inch to approximately 3 inches. For various reasons, such as corrosion or puncture, it can become necessary to replace the existing pipe with a new water pipe. Typically, this replacement process involves the digging of a trench in the ground along the path of the existing pipe to expose it, remove it and install a replacement pipe. Such trenches can be expensive and disruptive of landscaping and perhaps structures that have been placed over the existing pipe, and are therefore in the way of the trench which must be dug for pipe replacement.
The present invention is a device and method for the trenchless replacement of the existing pipe. A variety of trenchless pipe replacement devices and methods are known to exist. These devices and methods are designed for the replacement of sewer mains and laterals, and typically involve the fishing of a cable through the existing pipe followed by the attachment of a pipe bursting mole to the end of the cable, along with the attachment of the replacement pipe to the mole. Thereafter, utilizing a cable pulling device, the mole is pulled through the existing pipe, bursting it and pushing the pipe fragments outward, and the mole and replacement pipe are pulled through the existing pipe from one end to the other. At the completion of the pipe replacement process, the old pipe has been fragmented, such that the fragments remain in the ground, and the new replacement pipe has been pulled through the location of the existing, fragmented old pipe. Such prior art pipe replacement systems work well for larger diameter pipes, and pipes that fragment; however, they are not well adapted for the replacement of narrow diameter pipes, such as water pipes. As is discussed below, the present invention works by removing the existing pipe and replacing it with the replacement pipe.
The trenchless water pipe replacement device and method of the present invention includes a cable pulling device, a length of cable, a pipe splitting device and a cable end piece. The ends of the existing pipe are exposed, and the cable is fished through the pipe from a front end to a rear end. A cable end piece, that includes a relatively flat pipe end engagement surface, is then engaged to the end of the cable proximate the rear end of the pipe to be replaced. A suitable length of replacement pipe is then engaged to the cable end piece. At the front end of the cable a cable pulling device is engaged to the cable and a cable pulling device frame is engaged with the ground at the front end of the pipe. The cable pulling device can then be activated to pull the cable through the existing pipe, such that the pipe contacting surface of the cable end piece makes contact with the rear end of the pipe. Further pulling of the cable by the cable pulling device creates sufficient tension and pulling force on the rear end of the pipe that the pipe becomes dislodged from its location within the ground. Further pulling of the cable by the cable pulling device results in the existing pipe being pulled through the ground by the force of the cable end piece upon the rear end of the pipe, and the replacement pipe is pulled into the cavity due to its attachment with the cable end piece.
In a preferred embodiment, a pipe splitter is engaged at the front end of the pipe to split the pipe as it emerges. The pipe splitting device includes a tapered nose portion having a nose tip that is inserted into the front end of the pipe prior to the activation of the cable pulling device. The nose portion of the pipe splitter preferable includes a cable groove which guides the cable towards the cable pulling device, and a sharpened edge which serves as a splitting force focal point for splitting the pipe as it is pulled. In the preferred embodiment, the tapered nose is formed with a taper angle of from 1xc2x0 to 15xc2x0, and preferably approximately 2xc2x0. To place the cable pulling device out of a direct line of the emerging pipe, the pipe splitting device is preferable formed with an elbow having an angle of from 20xc2x0 to 90xc2x0, and preferably approximately 30xc2x0 to 35xc2x0.
It is an advantage of the present invention that a device for the trenchless replacement of water pipes has been developed.
It is another advantage of the present invention that a trenchless water pipe replacement device has been developed in which the existing pipe is removed from the ground and a replacement pipe is inserted at the location of the removed pipe.
It is a further advantage of the present invention that a pipe splitting device is utilized to split the existing pipe as it is removed from the ground in order to facilitate its removal.
These and other objects and advantages of the present invention will no doubt become apparent to those skilled in the art upon reading the following detailed description which makes reference to the several figures of the drawing.